The overall goal of this project is to develop a robust magnetic resonance spectroscopy (MRS) methodology to reliably measure cerebral GABA concentration in both the clinical and research settings. At present GABA spectroscopy sequences are limited by large voxel size and long imaging times. The present proposal seeks to develop a spectroscopy methodology, which can be used to look at a definite functionally relevant portion of brain parenchyma in a time short enough for the patient to remain consistently still; it also needs to remain sensitive to changes in GABA produced by the underlying pathology. The project also aims to demonstrate that the developed methodology is sensitive enough to detect a 20% change in GABA concentration with a 95% confidence interval. Upon completion, this methodology should be useful in studying GABA level at specific cortical regions in a number of neuropsychiatric patient populations (e.g. depression, hepatic encephalopathy, focal dystonia, cocaine abuse patients, juvenile myoclonic epilepsy, and panic disorder) marked by reduction in GABA concentration. This study aims to develop a MRS methodology based on MEGA-PRESS sequence for GABA editing to reliably measure GABA for the first time in the motor cortex of a normal control population. First year of this two year long study will be dedicated in developing the methodology by scanning phantoms and normal controls in a 3 Tesla Siemens Trio scanner and in the second year more scans will be performed to demonstrate the sensitivity of the methodology. [unreadable] [unreadable] [unreadable]